High speed electronic variable control of fluid flow using inexpensive batch fabricated valve arrays is potentially critical for numerous applications, including distributed actuator controls, paper or object positioning, dynamic control of fluid instabilities, or microcontrol of microchemical reactions and biological assays. Other potential applications include use of valves to drive physical elements that support tactile displays or other virtual reality interface tools. Gray level control valves provide greater control of fluid flow and are therefore more desirable than binary control valves. Also high speed valves with high throughput are difficult to manufacture inexpensively due to the large energy required to drive a massive mechanism.
By creating an array of small valves, variable high speed flow control is more easily and inexpensively obtainable and the throughput of the array in parallel allows unlimited throughputs. Matrix addressing may or may not be necessary depending on the number of flow levels and flows needed.
Each valve includes a valve housing having an aperture plate defining an aperture therethrough, and an opposing plate positioned in spaced apart relationship to the aperture plate. In one embodiment, a flexible electrically conductive film or strip is attached at its first end to the aperture plate and at its second end to the opposing plate. In another embodiment, a flexible electrically conductive film or strip is attached at one end and is free to move at the other end. In both embodiments, valve action is provided by use of switching electrodes for variably moving the flexible film between an aperture blocking position and an aperture open position. The aperture is an elongated opening, the operative size of which can be continuously varied or discretely varied by varying the voltage applied to the electrodes to control the movement of the film.
The valves of the present invention may be configured in an array of high speed valves which allows for high speed, high resolution, contactless transport of objects, including flexible objects such as paper. For certain applications, including processing of high purity or delicate materials, contamination or damage to the object may result from mechanical grasping or contact. This is particularly true for high speed processing systems, which may damage objects simply by engaging them. For example, high speed rollers may damage paper through differential engagement of misaligned paper with the roller, resulting in ripping or tearing of the paper. Fortunately, mechanical or frictional engagement is only one possible means for moving an object. Object drive mechanisms based on various fluid support techniques have long been employed to move delicate objects without requiring solid mechanical contact. For example, instead of using conventional belts, conveyors or rollers, paper moving through xerographic copier systems can be supported on a laminar air flow, or uplifted and moved by valve controlled air jets. This is particularly advantageous, for example, when sheets of paper carrying unfixed toner images must be moved between a photoconductive drum and a fusing station where the toner image is fixed. With conventional physical rollers, the continuing possibility of dynamic distortions to the toner image, or even slight misalignments resulting in image degradation, must always be considered.
Additional functions, objects, advantages, and features of the present invention will become apparent from consideration of the following description and drawings of preferred embodiments.